Refrigeration apparatus having an air pump circuit



Nov. 8, 1949 N. MORRIS 2,437,063

REFRIGERATION APPARATUS HAVING AN AIR PUMP CIRCUIT Filed 4 m 26. 1944 aSheets-Sheet 1 f W11)! I v 5 QbabV a/W 9160 0143: BY

JIE-E-a 04 &

' ATTOLQ/VEY Nov. 8, 1949 N. MORRIS 2,487,063

REFRIGERATION APPARATUS HAVING AN AIR PUMP CIRCUIT Filed April 26. 19448 Sheets-Sheet 2 4 4 I; r. d 40 INVENTOR. 96a 66 a -v Q'I'Cwmba Nov. 8,1949 N. MORRIS 2,437,058

REFRIGERATION APPARATUS HAVING AN AIR PUMP CIRCUIT Filed April 26, 1944e Sheets-Sheet s IRE- E L97 v @3 7 i INVENTOR.

T Shir/60w 9760/2314 J BY Nov. 8, 1949 N. MORRIS REFRIGERATION APPARATUSHAVING AN AIR PUMP CIRCUIT Filed April 25, 1944 8 Sheets-Sheet 4INVENTOR. S'Gal'aw Qfiaomio,

I REFRIGERATION APPARATUS HAVING AN.AIR PUMP CIRCUIT A Filed April 2.6.1944 N. MORRIS Nov. 8; 1949.

8 Sheets Sheet 5 INVENTOR. 9Gala-v 9130/0116,

krro Awvs r N. MORRIS 2,487,068 REFRIGERATION APPARATUS HAVING AN AIRPUMP CIRCUIT Nov. 8, 1949 8 Sheets-Sheet 6 Filed April 26, 1944INVENTOR. v a W 97190 01443 A TO/QA/f Y N. MORRIS REFRIGERATIONAPPARATUS HAVING AN AIR PUMP CIRCUIT -8 She ets-Sheet 7 a I L 4 4 4/ ,TM a/ a w WW 4 W m w 7 2 F w "IN V EN TOR.

cLM 312904:

Nov. 8 1949 N. MORRIS 2,487,068

REFRIGERATION APPARATUS HAVING AN AIR PUMP CIRCUIT Filed April 25, 19448 Sheets-Sheet 8 YET-E E INVENTOR. 90a [1641M 9727042214) Arron/v5 0Patented Nov. 8, 1949 I UNITED STATES PATENT OFFICE REFRIGERATIONAPPARATUS HAVING AN Am rum cmcurr Nathan Morris, Silver Spring, Md.,assignor; by mesne assignments, to American Instrument 00., Inc., acorporation of Maryland Application April 26, 1944,v Serial No. 532,8075 Claims. (01. 82-6) 1 My invention relates broadly to refrigeration andmore particularly to the system and apparatus for producing sub-zerotemperatures.

One of the objects of my invention is to provide a method of controllingextremely low tem-- peratures in a refrigeration cabinet. with a highdegree of precision.

Another object of my invention is to provide a construction of apparatusfor producing and maintaining relatively low temperatures in a cabinetutilizing solidified gas as the refrigerant.

Still another object of my invention is to provide a refrigerationapparatus having a solidified gas refrigeration cabinet with acirculator therein for cyclicly pumping low temperature gas through awork chamber.

A further object of my invention is to provide a construction ofcirculator and volume control unit which may be readily installed in asolidifled gas refrigeration cabinet on a quantity production basis.

Still another object of my invention is to provide a construction ofseal between externally arranged driving motors and fans internallyarranged within a refrigeration cabinet for minimizing refrigerationloss transfer between the exterior and interior of the cabinet.

A further object of my invention is to provide a construction ofobservation window for subzero refrigeration cabinets including meansfor minimizing refrigeration loss.

A still further object of my-invention is to provide a construction ofwork chamber for subzero cabinets including means for permitting anoperative to extend his arms through especially prepared sleeve-likeapparatus in the wall of the cabinet for manually working within thecabinet while minimizing refrigeration loss.

A further object of my invention is to provide a system of dual fanoperation for low temperature refrigeration cabinets with means forcooperatively controlling the operation of the fans whereby one of thefans may be constantly driven for maintaining circulation of therefrigerating gas within the cabinet while the other of the fans isintermittently driven according' to the temperature requirements for theparticular work being performed within the cabinet.

Other and further objects of my invention reside in the method ofoperation and details of construction of the refrigeration apparatus setforth in the specification hereafter following by reference to theaccompanying drawings in which: Figure l is a plan view of oneconstruction of refrigeration apparatus embodying my 2 invention; Fig. 2is a vertical sectional view taken on line 2-2 of Fig. 1; Fig. 2a is adetailed view showing one arrangement of sealing the entrance way forthe shaft which connects one of the external driving motors to one ofthe gas circulating fans in the cabinet structure; Fig. 3 is ahorizontal sectional view through the cabinet structure takensubstantially on line 3-3 of Fig; 2; Fig. 4 is a transverse verticalsectional view taken through the cabinet structure substantially on line4-4 of Fig. 3; Fig. 5 is a vertical sectional view through the cabinetstructure taken substantially on line 5-5 of Fig. 6; Fig. 6 is a planview similar to the plan view of Fig. 1, but illustrating one section ofthe hinged top of the cabinet opened to show the interior of the Dry Icecompartment; Fig. '7 is a detailed sectional view of the blower andassociated duct and volume controlling valve employed in associationwith the Dry Ice compartment; Fig. 8 is a horizontal sectional viewthrough the blower taken substantially on line 88 of Fig. 7; Fig. 9 is avertical sectional view through the blower and associated duct and valvesystem taken substantially on line 9-9' of Fig. 7; Fig. 9a is aperspective view broken away and illustrated in section of the rotorused in the blower system of my invention; Fig. 10 is a verticalsectional view through the blower and associated duct system takensubstantially on line Ill-10 of Fig. '7; Fig. l1 is a detailedperspective view of one portion of the blower housing; Fig. 12 is aperspective view of the supporting plate used in association with theblower housing; Fig. 13 is a horizontal sectional view showing the valvestructure used in association with the duct system of the blower; Fig.14 is a transverse sectional 'view through the valve structure on linel4-|4 of Fig. 13; Fig. 15 is a top plan view of the duct system andassociated gas deflector plate with parts broken away and illustrated insection to show the blower within the blower housing associated with theduct; Fig. 16 is a perspective view of the blower unit duct andassociated control valve; Fig. 17 is a front elevational view-of thecontrol valve for controlling the gases that are pumped from the Dry Icecompartment into the work compartment; Fig. 18 is a detailed sectionalview through the observing window in the cabinet with the groups ofplate units making up the observation window for the refrigerationcabinet; Fig. 20 is a wiring diagram illustrating the electrical circuitarrangement for the control units employed in the refrigeration systemof my invention; Fig. 21 is a vertical sectional view through a modifiedform of cabinet structure embodying my invention, the view being takencentrally through the Dry Ice compartment and through the workcompartment; Fig. 22 is a view similar to the view illustrated in Fig.21 where the section is taken in a position to illustrate the ductleading from the blower in the Dry Ice compartment to the workcompartment; Fig. 23 is a detail view taken through one of the handholes provided in the side wall of the cabinet structure; Fig. 24 is anelevational view showing one of the plugs in position for closing'thehand hold, parts being broken-away and shown in section to more clearlyillustrate liner for the hand hole; Fig. 25 is an elevational view ofone of the protective sleeves used in association with one of the handholes in the side wall of the cabinet, the view being broken away andshown in section; and Fig. 26 is an end view of the protective sleeveillustrated in Fig. 25.

Referring to the drawings in more detail reference character idesignates the refrigeration cabinet embodying my invention and in whichlaminated insulation material having high heat insulation propertiesconstitutes the wall structure of approximately six inches in thickness.The insulation material is covered externally by suitable heatinsulation surfacin material such as laminated board represented at 2.The interior of the cabinet is provided with a metallic liningrepresented at 3which has all joints well filled and caulked toeliminate insofar as is practicable the loss of refrigeration by heattransfer through the walls of the cabinet. A cover formed in sectionsrepresented at 4 and 5 hinged together as represented at 6 extends overthe cabinet structure and is secured in tight sealed relation thereto byhasps l which when forced into securing position insure a gas-tightjoint between the metallic peripheral extension 8 of the lining 3 andthe metallic facing 9 and ll! of the cover sections 4 and 5. The coversections 4 and 5 are constructed in a manner similar to the constructionof the main cabinet in that the internal laminated heat insulation isfaced on its lower surface by metallic material 9 and I and covered onthe peripheral edges and upper surface by laminated wood or otherinsulation material indicated at H.

The interior of the cabinet is divided into a work chamber representedat l4 and a Dry Ice compartment represented at lby means of a partitionI6 of insulation material. The partition l6 extends transversely of theinterior of the cabinet termination above the bottom of the cabinet atll. The partition is formed from laminated insulation material enclosedby metallic sheet-like material represented at l8, one surface of whichforms the transverse wall of the work compartment 14 and the oppositesurface of which I9 constitutes one wall of the Dry Ice compartment. TheDry Ice compartment which terminates at the level I! is arranged toreceive a basket or box-like carrier represented at that is providedwith-an openwork meshlike side 2| atone end thereof for the freecirculation of gases under control of the blower represented generallyat 22.

The blower and the accessories associated therewith are shown moreclearly in Figs. 7-16. The blower includes mounting means in the form ofa circular plate 23 illustrated in Fig. 12 which 4 is secured by screws24 through the interior side wall of the cabinet with the centralaperture 25 thereof arranged concentrically with and fitting over theprotruding end of tubular member 28 that extends through the side wallof the cabinet and serves as a guide through which the drive shaft 21extends. Drive shaft 21 is connected to motor 28 supported externally ofthe cabinet on suitable mounting bracket 29. A sealing gland is providedbetween motor 28 and the external side wall of the cabinet asrepresented at 30 for preventing loss of refrigeration. The sealinggland comprises a substantially resilient gasket which is compressedbetween the end of the motor frame 28 and the side wall of the cabinet 7for substantially preventing heat exchange through the tubular member26.

The supporting plate 23 is provided with a plurality of radiallyextending tongues or oilset lugs indicated at 3| spaced from the sidewall of the cabinet sufficiently to permit one portion of the housingfor the fan represented at 32 to have the aperture 33 therein withradially disposed notches 34 which extend therefrom to be aligned withand slipped over lugs 3!. When the housing 32 is assembled in positionit is slightlyv sition by screws 24.

The rotor shown more particularly in Figs. 8, 9 and 9a at 35 may now bereadily mounted on shaft 2'7 by engagement of set screw 36 in hub member3? thereof with the shaft 21. The rotor 35 is pressed from sheet metaland provides a multiplicity of radially extending fan blades 38 whichare effective to develop a very substantial gas flow through the fanhousing. With the fan 35 mounted in position, the coacting side portionof the fan housing shown at 39 is mounted in position in the fan housing32 with the aperture 40 therein registering with the end of the rotor 35constituting the fan. The intake for gases is established through thecenter aperture 40 of the housing which is in close proximity with theopen mesh side wall 2| of the Dry Ice container 20. The delivery end ofthe fan 35 is connected to the duct system 4| which, when the fanhousing is properly mounted in position, extends vertically in the DryIce compartment and forms a slip connection coupling means with thedepending end 42 of the elbow 43 of horizontally extending duct 44. Thehorizontally extending duct 44 contains deflector or streamlining guideplate 45 therein for reducing friction to gas flow through the ductsystem. The end of the horizontally extending duct 44 projects through arecess 44aformed in the partition I6 and projects into the upper portionof the work compartment l4. The end of the duct 44 is provided with atransversely extending frame member 41 which fits thereon and serves asa guide for an adjustable plate member 48 which may be adjusted betweensets of coacting guide grooves indicated at 43 and 50. The adjustableplate 48 has a projecting finger grip portion 5| enabling the plate tobe manually grasped and moved to selected positions to fully In order toconfine the forced gas fiow into the work compartment from therefrigeration compartment to the duct system I provide a deflector plate63 which extends from the top of the guide plate frame 41 to a positionestablishing sealed relation with the entire surface of the coversection 4. As represented in'Flg. 4 the deflector plate 53 extends onlypartially across the cabinet forcing the gases to pass through theconfined space indicated at 46 so that the return gases are free to passthrough the elongated slot or recess indicated at 46 in their convectionpath from the work compartment into the refrigeration compartment.

In addition to the blower 22 which I have described I also provide anarrangement of fan 55 which is mounted below the refrigerationcompartment centrally of the interior of the cabinet on shaft 56 whichextends through the tubular member 51 in the side wall of the cabinet tothe motor 58 supported on bracket 59 on the exterior of the cabinet. Acompressible gasket 68 is compressed between the end of tubular sleeve51 and motor housing 58 for providing a gas-tight seal and preventingheat exchange between the exterior atmosphere and the interior of thecabinet. An annular ring member 6| is secured against the gasket 60forcing the gasket 60 into tight sealing relation with the end of themotor'housing. An annular rim member 62 fits over the ring and gasket 60as shown. The fan 55 is located beneath the refrigeration compartmentand in line with the heaters 63 that are supported on frame 64 thatextends transversely of the cabinet immediately adjacent the partitionI6. The heaters 63 are constituted by wire coils which may be arrangedin sections and electrically connected in series or multiple arrangementfor securing different temperature conditions. 7

In Fig. 20 I have shown the switch system 85 which is mounted in acontrol box externally of the cabinet for determining the parallel orseries arrangement of the wire coils 63a and 63b which comprise theheaters 63. The connection of the heaters into the power supply circuit66 is controlled by mercury switch 61 actuated by armature 68 controlledby solenoid winding 69 which is energized or deenergized in accordancewith the position of the thermostat 18 the control element of whichextends into the cabinet as represented in Figs. 2, 3, 4, 21 and 22. Thethermostat is connected to the direct current control circuit whichincludes the rectifier bridge shown at H connected to secondary winding12 of transformer 13 whose primary winding 14 connects to the powersupply circuit 66. A main switch is provided for cutting off the entirecabinet electrical service f1 om the power supply line 66 which isusually 110 volts alternating current. The transformer l3 appropriatelysteps down the power supply to the thermostatic control circuit foroperation of solenoid winding 69. Fan motor 58 normally operatescontinuously although the condition of heat within the work chamber mayvary. Such condition is controlled by the cutting on or off of the wirecoils 63a and 63b of the heater 63 as the thermostat 10 may determine.Selector switch 65 is manually controlled from the apparatus controlpanel exterior of the cabinet structure for connecting thewire coils 63aand 63b in parallel in order to obtain maximum temperature conditions orconnecting the wire coils 68a andv 63b in series in order to obtainlower temperature conditions or to select merely a single wire coil andeliminate the other wire coil from the circuit in order to obtain mediumtemperature conditions.

In addition to the mercury switch 6! controlled by member 68 which isoperated by solenoid winding 69, I also provide a coacting mercuryswitch 11 having its contacts connected to selector switch 18 to thepower supply line 66 and to the blower motor 28. Selector switch 18 ismanually controlled from the apparatus control panel externally of thecabinet structure and when moved to contact 19 places the blower motorunder control of mercury switch TI, but when moved to contact 88eliminates the control of blower motor 28 from contacts 11 and allowsthe blower motor 28 to run continuously except as may be determined bythe externally manually controlled switch 8| mounted on the apparatuspanel. An alternative of this arrangement includes a provision ofresistors allowing blower motor 28 to be continuously controlled bymercury switch 11 at different speeds. The manually operated switch 8|when closed places blower motor 28 under control of the set of contactsin mercury switch 11 assuming manually controlled switch 18 to be movedto contact 19. So long as blower motor 28 is operating pilot lamp 82 islighted through suitable power reducing resistor 83, the pilot lamp 82and resistor 83 combination being effectively inparallel with blowermotor 28 and the power supply line 66. Without pilot lamp 82 operatingon the apparatus control panel externally of the cabinet, the operatingcondition of blower motor 28 cannot readily be determined inasmuch asobservation into the cabinet from the exterior thereof is restricted toa relatively small observing windowand the sound of the running blowerwithin the cabinet is substantially mufiled by the cabinet structure. Asuitable convenience outlet represented at 84 is connected in a shuntwith the power supply line 66 and mounted on the apparatus control panelexternally of the cabinet structure.

I have heretofore alluded to the observing window of the cabinetstructure and invite attention to Figs. 18 and 19 for a more detailedunderstanding of the special construction that I have developed forpreventing heat exchange between the interior and exterior of thecabinet. The window is made up of groups of vacuum sealed glass panelsrepresented at 85 and 86. The group 85 consists of a pair of platesspaced at their peripheries by spacer member 81 with the air evacuatedfrom the space therebetween. The group of plates 86 consists of two setsof plates spaced at their peripheries as indicated at 88 and 89 with theair evacuated from the space therebetween. These two sets of plates arespaced by the intermediate frame represented at 88 consisting of fiatstrips mutually interfitting with each other by coacting slots formed inthe strips and apertured in the sides thereof as represented at 9|to'allow fiow of air from the space between the groups of platesrepresented at 92 and the space behind the plates represented at 93within which bags of silica-jell 94 are arranged. The silica-jell in thebags at 94 possesses a high degree of affinity for absorbing moisturewhich may develop between the groups of plates in consequence of theirsubjection to violent temperature changes. The sets of plates and thespacing strips 90 therebetween are set into the recess 7 99 in theaperture 96 which extends through the wall of the cabinet and aresecured in position by means of suitable molding 91 extending around theoutside marginal edge of the aperture 95 external to the cabinet. Thusthe observing window permits full vision of the interior of the workingchamber it while preventing heat exchange between the interior andexterior of the cabinet.

As illustrated in Figs. 21 and 22 I may arrange the observingwindow inone of the side walls of the, cabinet structure in the positionrepresented at." to permit observation of operations which may becarried out in the working chamber 84 where the arms of the operativemay be passed through arm holes provided adjacent the observation windowin the wall of the cabinet as represented at 99. The arm holes 99 arenormally closed by plugs of insulation material represented at I09.

I have shown the plugs more clearly in Figs. 23 and 24. It will beobserved that the side walls of the cabinet I is formed from insulationmaterial having an inner metallic lining 3 andan exterior laminatedfacing 2 lined by a tubular sleeve member ifil. The tubular sleevemember iill is formed from insulation material and has opposite ends ofreduced section one of which shown, at it: fits through an aperture weformed in metallic lining 3 and the other of which shown at its projectsbeyond the external laminated facing 2 of the cabinet and is securedwith respect thereto by a ring member Hi5. The joints are all caulkedfor preventing heat exchange. The tubular member is internally groovedas repre sented at 596 and serves as a securing means for the canvassleeve it? which Ihave shown more particularly in Figs 25 and 26. Thecanvas sleeve it? is tapered in structure and serves as an arm coveringthrough which the operative may project the arm with the canvas sleeveI01 snugly fitting about the arm as an extended cover therefor. Thegroove 106 is formed adjacent the working chamber end of the tubularmember it! and serves as a securing means for the end of sleeve i9?therein by reason of the arrangement of the resilient expandible ringI08 which clamps the sleeve adjacent the inner face of the tubularmember. The opposite end of the sleeve it! terminates in an elasticwrist band H09 through which a gloved hand of the operative may bethrust for maintaining the passage through the tubular membersubstantially closed while the arm of the operative is extended throughthe tubular member. With the plug I removed the operative inserts thegloved hand through the elastic wrist band I09 and then projects the armwholly into the work chamber i4.

Inasmuch as both arms of the operative may thus be extended into theworking chamber it and operations in the working chamber l4 observedthrough window 98, it is possible to perform various adjustments andoperations within the working chamber at sub-zero temperatures withoutallowing excessive entry of heat from the exterior of the cabinet intothe working compartment l4 and without allowing appreciable leakage ofrefrigerant.

The plug I00 consists of multiple layers of insulation materialrepresented at I000. confined in stacked relation by suitable boltmembers lllflb which may also serve as securing means for handle memberH0 enabling the orifice to be immediately plugged after an operationthereby preventing excessive drop in temperature within the workingcompartment i l.

8 The cabinet is installed in a location away from heated radiators ordirect sunlight. It is mounted on a reasonably level floor or platformand the power circuit 96 connected to a suitable power source such as110 volt 60 cycle alternating current. I find it desirable to ground thecabinet, power service conduit system and interior of the cabinet wallas represented schematically at land 2 in Fig. 20.

Dry Ice represented generally in commercial block form at i5 isdeposited in basket 20. the work set up in the working compartment l4and the cabinet closed. The Dry Ice is pumped over as a gas into theworking compartment by blower 35 under control of the thermostat l9 andheater system 63. Assuming that a temperature 0! minus 50 degrees F. isdesired, ther-' mostat I0 is set for this temperature and locked.Calibration can be made by observing a thermometer inside the workingchamber and checking the thermometer reading the instant that the pilotlamp 82 is illuminated on the control panel exterior to the cabinetwhich shows the instant that the blower motor 28 is energized for theminus. 50 degrees F. setting of thermostat 10.

Operation of cabinet at 40 deg. to 100 den. F.

In order to operate the cabinet over ranges, for example, of --40 to-100 F. the Dry Ice compartment 20 is filled to the top with Dry Icecrushed to approximately egg-size. It is advisable not to use powderedor too finely pulverized ice as it increases the surface area-,- and, inturn,

of degrees F., it may be necessary to recharge the Dry Ice compartmentwith more Dry Ice which, in turn, increases the surface area and rapidlybrings the box down to degrees F.

For any temperature control in the range of -40 degrees F. to -100degrees F., the slide damper 48 shouldbe adjusted to half-open position.Simply set the regulator it for the desired temperature in this rangewith the heat switch 65 in the oil position, and it will givesatisfactory regulation.

For temperatures from 0 degrees to -40 degrees F., the slide damper 48should be in the open position.

When working at or near 0 degrees F. or above, it is advisable to putthe Dry Ice in in as large lumps as possible (normally 1 or 2 pieceswhich will fill compartment). This provides better control at thesetemperatures. It may also be necessary at any temperature from 20degrees on up to room temperature to turn the heater switch 65 to lowposition to compensate for leakage through the interior insulation.

Operation from room temperature to 220 degrees F.

The same procedure is followed for setting the thermoregulator 10 forthese higher temperatures. Any Dry Ice that may be present in the boxshould be removed, and the heater switch 65 turned to high until desiredtemperature is reached. It will require from 3 to 4 hours for the box torise from room to 220 degrees F. with the switch on high. Switchpositions are as follows:

From room to 120 degrees F.: "low From 120 degrees F. to 160 degrees E:"medium From 160 degrees F. to 220 degrees F.: "high" In opening the lidof the box at the high temperatures, it is advisable that no fan ordraft of cool air be made to strike the observation glass at theunderside of the lid as sudden change of temperature might crack theglass.

Safety thermostat In order to avoid dangerous conditions which mightresult from failure of the thermostat HI to function, I provide a safetythermostat H6 in the heater circuit which will open at approximately 230degrees F. rreventing the box from rising any higher than this, therebycausing damage. This safety thermostat may be conveniently located onthe lower left-hand of the heater frame 64.

Normal Dry Ice consumption at 100 degrees F. after the initial pull-downis approximately 2 lbs. per hour. Dry Ice consumption at -40 degrees F.is approximately 1.5 lbs. per hour. Dry Ice consumption at degrees F.,with heat switch on low heat (input 125 watts) is approximately 2 lbs.per hour. Dry Ice consumption at 0 degrees F., with no heat on and DryIce in one large piece, is approximately 1.25 lbs. per hour.

The equipment of my invention is highly practical inasmuch as Dry Ice isnow commercially obtainable through wide distribution channels andprovides a convenient means for securing refrigeration at thetemperatures obtained in the system of my invention.

The only maintenance required with the equipment is the occasionaloiling of the fan motor 58 and blower motor 28. Replacement of the pilotlight 82 is readily made. It may be necessary to renew the heater coils63a and 63b from time to time.

The apparatus of my invention has wide application in industry such asthe shrinking of rivets for mass production rivetin operations, thechilling of aluminum rivets to retard hardening and maintain them softenough for driving; the storing of metal parts at low temperatures forconditioning the parts prior to use as in chilling the parts forexpansion fitting; the treating of tool and other steels by chilling toproduce desired characteristics otherwise difficult to obtain byordinary methods of treatment; the accelerated ageing of metals; thestoring of serums, blood, chemicals, etc.; the testing of aircraftequipment and materials of every description for determining theirdurability, performance, etc.

at low temperatures and as a food-freezing pilot plant. The portabilityof the equipment is one of its outstanding features in addition to itslow cost and simplification of design for quantity production. v

In the operation of the refrigeration apparatus of my invention the gasfrom the solidified gas compartment is accumulated in a confined area orcolumn in the duct system -44 which serves as a trap from which the gasdoes not run out until the blower fan is initiated in motion.

The confined column of .gas is then lifted by the fan 35 and pumpedthrough the work compartment for maintaining the sub-zero temperaturetherein. This process of lifting and pumping the column of gas continuesuntil the predeteriii) 10 mined thermostat controlled temperature in thework compartment is reached.

Wherever in the specification and/or claims I may use the expression dryice I desire that this be understood to mean any solidified gas. Myinvention is not restricted to the use of CO2 as any solidified gas maybe employed for securing the sub-zero temperatures obtainable in theapparatus of my invention.

Although I have described my invention in certain of its preferredembodiments, I realize that changes and modifications may be made and Iintend no limitations upon my invention other than may be imposed by thescope of the appended claims.

What I claim as new and desire to secure by LettersPatent of the UnitedStates is as follows:

1. Refrigeration apparatus comprising a cabinet structure including .asolidified gas refrigeration compartment and a work compartment, ablower disposed adjacent the base of said solidifled gas refrigerationcompartment for pumping gas therefrom into said work compartment, a ductconnected with said blower and extending vertically within saidrefrigeration compartment and horizontally into said work compartmentfor delivering refrigerated gas thereto a circulator disposed in saidwork compartment, and means for intermittently operating said blower andcontinuously operating said circulator.

2. Refrigeration apparatus comprising a cabinet, a transverselyextending partition dividing said cabinet into a work compartment and asolidified gas refrigeration compartment, said partition being recessedadjacent the top and bottom thereof, a removable top extending acrosssaid cabinet in a position in which a predetermined gap is maintainedbetween the top recess in said partition and the under-surface of thetop that extends across the cabinet, a blower disposed adjacent the baseof the solidified gas refrigeration compartment, a duct connected withsaid blower and extending through said partition and into said workcompartment, a deflector plate intermediate the top recess in saidpartition and the under-surface of the top of said cabinet structureadjacent the passage of the duct through the partition and operating torestrict the return passage for circulating gas from said workcompartment to the solidified gas re 'rigeration compartment to a pathimmediately adjacent said solidifled gas compartment between the toprecess in said partition and the under-surface of said cabinet. v

3. In a temperature controlled cabinet, a heat insulated wall structureforming a refrigeration cabinet, a substantially circular plate membersecured to the interior surface of said wall structure and apertured forthe passage of a drive shaft therethrough, a driving motor mountedexteriorly of said wall structure and connected with said drive shaftfor rotatably driving the drive shaft, an annular skirt formed on saidplate member lugs extending radially from the annular skirt of saidplate member in positions spaced from the interior wall of said cabinet,2. fan housing having an opening in one side thereof recessed to coactwith the lugs carried by said plate member and insertable over saidplate member with said lugs passing through the recesses therein, saidhousing being angularly movable to a position in which the housing issecured in operative position by the coaction of said lugs with theinner periphery of the opening in the housing, a duct connected withsaid wall, lugs projecting radially from said plate in position spacedfrom the interior surface of v the wall of the cabinet, said plate beingapertured for the passage of a motor drive shaft.

a motor mounted exteriorly of said cabinet and having its drive shaftextending through said heat insulated 'wall and through said platemember, sealing means between said. motor and the entrance of said shaftthrough said wall structure, a fan housing angularly movable from anassembly position to an operating position within said cabinet, said fanhousing having an opening recessed at the periphery thereof for thepassage of said plate and the lugs thereon, the said housing beingengageable at the periphery 'of said opening by the lugs on said platewhen the housing is shifted to operating position within said cabinetstructure, a duct connected with said housing and extending into saidrefrigera tion cabinet and a fan carried by said shaft within saidhousing.

5. Refrigeration apparatus comprising a cabinet, a transverselyextending partition dividing said cabinet into a work compartment and asolidified gas refrigeration compartment, said partition being recessedadjacent the top and bottom thereof, a removable top extending acrosssaid cabinet in a position in which a predetermined gap is maintainedbetween the top recess in said partition and the under-surface of thetop that extends across the cabinet, a blower disposed adjacent the baseof the solidified gas refrigeration compartment, a duct connected withsaid blower and extending through said partition and into said workcompartment, a

12 deflector plate intermediate the top recess in said partition and theunder-surface of the top of said cabinet structure adjacent the e of theduct through the partition and operating to restrict the return passagefor circulating gas from said work compartment to the solidified gasrefrigeration compartment to a path immediately adjacent said solidifiedgas compartment between the top recess in said partition and theunder-surface of said cabinet, the top recess in said partition abovesaid solidified gas refrigeration cabinet being open for the returnpassage of gas from the work compartment to said solidified gasrefrigeration compartment, and means in said duct r substantiallycoplanar with said partition for variably controlling thevolumetridtransfer of gas from said solidified gas refrigerationcompartment to said work compartment.

NATHAN MORRIS.

REFERENCES c rrEn The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 123,077 Bate Jan. 30, 18721,124,778 Meuler Jan. 12, 1915 1,145,054 Boekel et al. July 6, 19151,269,612 Knoerr June 18, 1918 1,848,440 Spitzenberger et al. Mar. 8,1932 1,934,864 Lambert et al Nov. 14, 1933 2,019,907 Jensen Nov. 5, 19352,046,967 Post July 7, 1936 2,243,999 Chapple June 3, 1941 2,266,346Vincent Dec. 16, 1941 2,359,796 Russell Oct. 10, 1944 2,377,590 TalalayJune 5, 1945 FOREIGN PATENTS Number Country Date 359,984 Italy June 9,1938

